This invention relates to rain-tight compression fittings, and more particularly to fluid-tight compression fittings for electrical metallic tubing.
Electrical metallic tubing (xe2x80x9cEMTxe2x80x9d) conduit is a metal conduit that encases electrical wiring. Typically, the conduit is thin-walled and non-threaded. The EMT conduit is used to enclose electrical wires in, for example, warehouses and manufacturing facilities where the wiring may be run along the walls and the ceiling such that the conduit is exposed. Where the electrical wiring and the surrounding EMT conduit connect to an electrical device, such as a motor, transformer, or fuse box, there must be a rain-tight seal between the EMT conduit and the electrical device. Typically, a ring is used to connect the EMT conduit to an EMT body, which may be a connector protruding from the electrical device. When the rain-tight seal is formed, an electrical ground continuity between the EMT conduit and the EMT body also may be formed.
In one general aspect, a connector assembly includes a nut, a first member, a second member, and a third member. The connector assembly is used for coupling a conduit to an electrical device that includes a body having an end with an outer edge and a threaded exterior surface. The nut includes a first angled end, a second threaded end, and an inner cavity between the first angled end and the second threaded end. The nut is configured to be threadably attached to the threaded exterior surface of the body. Each of the first, second, and third members includes first and second edges, is positioned within the cavity, and encloses the conduit when the conduit is connected to the body. When the nut is threadably attached to the body, the first edge of the first member slidably mates with the first angled end of the nut, the second edge of the first member is in contact with the first edge of the second member, the second edge of the second member is in contact with the first edge of the third member, and the second edge of the third member slidably mates with the outer edge of the end of the body.
Implementations may include one or more of the following features. For example, the first member may include a compression ring, the second member may include a friction washer, and the third member may include a sealing ring. The first member may include a sealing ring, the second member may include a friction washer, and the third member may include a compression ring.
The first member may include a first wall including the first edge of the first member, a second wall including the second edge of the first member, and a top wall, and, when the nut is threadably attached to the body, one or both of the first wall and the second wall are in a penetrating contact with an outer surface of the conduit.
The third member may include the first edge of the third member, the second edge of the third member, a third edge connecting the first edge of the third member and the second edge of the third member, and a fourth edge connecting the first edge of the third member and the second edge of the third member, and, when the nut is threadably attached to the body, the third edge of the third member is compressed against the conduit. The fourth edge may be compressed against the nut.
The second member may include a third edge connecting the first edge of the second member and the second edge of the second member and, when the nut is threadably attached to the body, the third edge of the second member is compressed against the nut. The second member may have a triangular or rectangular cross-section.
One of the first edge of the first member and the second edge of the third member may form a fluid-tight seal against the conduit. One of the first edge of the first member and the second edge of the third member may form an electrical ground continuity between the conduit and the nut. The conduit may be an EMT conduit and the body may be an EMT body.
In another general aspect, coupling a conduit to an electrical device includes providing a body having an end with an outer edge and a threaded exterior surface, providing a conduit, providing a connector assembly including a nut, and threadably attaching the nut to the body. The connector assembly includes the nut, a first member, a second member, and a third member. The nut includes a first angled end, a second threaded end, and an inner cavity defined between the first angled end and the second threaded end, the nut being configured to be threadably attached to the threaded exterior surface of the body. The first member includes a first edge, a second edge, is being positioned within the cavity and configured to enclose the conduit when the conduit is connected to the body. The second member includes a first edge, a second edge, and is positioned within the cavity and configured to enclose the conduit when the conduit is connected to the body. The third member includes a first edge, a second edge, and is positioned within the cavity and configured to enclose the conduit when the conduit is connected to the body.
Implementations may include any of the features described above.
The connector assembly provides considerable advantages. For example, the connector assembly provides a fluid-tight seal, an electrical ground continuity, and a strong joint between an EMT conduit and an EMT body in which the EMT conduit is installed. The strong joint resists pulling the conduit from the body. The components of the connector assembly are relatively simple, and are easily and inexpensively produced, such that the connector assembly may be inexpensive and easy to use.
The details of one or more implementations are set forth in the accompanying drawings and the description below. Other features and advantages will be apparent from the description, the drawings, and the claims.